Update: This adapter only works with the enterprise edition of Sybase (i.e. Sybase ASE) not with SQLAnywhere (Sybase ASA)
One of my Rails projects require me to connect to a Sybase ASA database, I quickly figured out that I needed to install the sybase adapter as in Rails 2.0.2 these and some of the other databases have been pulled out of Rails core. According to the information in this article you can achieve this by using this command:
gem install activerecord-sybase-adapter
When I tried this I got the following error:
ERROR: could not find activerecord-database-adapter locally or in a repository
The only way I got it to work was to use the -s option ("Use URL as the remote source for gems"), i.e.
gem install activerecord-sybase-adapter -s http://gems.rubyonrails.org